1. Field of the Invention
The present invention is directed in general to semiconductor devices and methods for manufacturing same. In one aspect, the present invention relates to wire ball bonding and associated methods of fabricating and testing same.
2. Description of the Related Art
Ball bonding is widely employed in the semiconductor packaging industry to form electrical connections between an integrated circuit die and a die carrier such as a lead frame or a substrate. Conventional ball bonding processes typically use a combination of heat, pressure and ultrasonic energy to form an intermetallic connection or weld between a wire and a connection pad. However, the connection pad is typically subjected to a number of stressors such as impact force, contact power, contact force, bond power and bond force during the ball bonding process, leading to mechanical integrity problems, such as cracks between the connection pad and bonding ball that can form during bonding, device operation or device testing, such as highly accelerated stress test (HAST). Such reliability concerns are exacerbated with copper ball bonds which have a narrower process window than with gold ball bonds.
It will be appreciated that for simplicity and clarity of illustration, elements illustrated in the drawings have not necessarily been drawn to scale. For example, the dimensions of some of the elements are exaggerated relative to other elements for purposes of promoting and improving clarity and understanding. Further, where considered appropriate, reference numerals have been repeated among the drawings to represent corresponding or analogous elements.